On the Difficulty of Establishing Interdomain LSPs
Cristel Pelsser, Steve Uhlig and Olivier Bonaventure
Nowadays, the success of MPLS is mostly due to the increasing demand
for BGP/MPLS VPNs. Even though the need for interdomain LSPs is growing,
no ISP today proposes the dynamic establishment of LSPs across AS
boundaries. In this paper, we investigate the complexity of establishing
end-to-end interdomain LSPs with QoS guarantees, based on the BGP routes
locally available at a router.
We explain the main issues of relying on BGP for the computation of
interdomain constrained paths. To illustrate our point, we compare two
LSP establishment techniques. Our benchmark technique is centralized and
assumes the complete knowledge of the intradomain topologies. The second
path computation technique isdecentralized and relies on the BGP routes
locally available by each router. Our simulations confirm that the
difficulty in designing BGP-based interdomain LSP establishment techniques
lies within the trade-off between the scalability of the computation
technique and the quality of the path found in terms of the considered
metrics.
In 2004 IEEE International Workshop on IP Operations & Management (IPOM 2004), 2004.
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